Semiconductor device capable of preventing moisture-absorption of fuse area thereof and method for manufacturing the fuse area

ABSTRACT

A fuse area of a semiconductor device capable of preventing moisture-absorption and a method for manufacturing the fuse area are provided. When forming a guard ring for preventing permeation of moisture through the sidewall of an exposed fuse opening portion, an etch stop layer is formed over a fuse line. A guard ring opening portion is formed using the etch stop layer. The guard ring opening portion is filled with a material for forming the uppermost wiring of multi-level interconnect wirings or the material of a passivation layer, thereby forming the guard ring concurrently with the uppermost interconnect wiring or the passivation layer. Accordingly, permeation of moisture through an interlayer insulating layer or the interface between interlayer insulating layers around the fuse opening portion can be efficiently prevented by a simple process. In addition, the etch stop layer is also formed under the fuse opening portion so that an insulating layer remaining on the fuse line can be controlled to have a predetermined thickness when forming the fuse opening portion, thereby improving the cutting efficiency of fuses.

This application is a Divisional of U.S. Ser. No. 10/334,745, filed onDec. 31, 2002, now pending, which is a divisional of U.S. patentapplication Ser. No. 09/650,967, filed on Aug. 29, 2000, now issued U.S.Pat. No. 6,525,398, which claims priority from Korean Patent ApplicationNo. 1999-36534, filed on Aug. 31, 1999, all of which are herebyincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device and a method formanufacturing the same, and more particularly, to the structure of afuse area and a method for forming the fuse area.

2. Description of the Related Art

Generally, semiconductor devices are formed by stacking material layersof various patterns and finally depositing a protection film called apassivation film. The passivation film, conventionally formed of a hardfilm such as a silicon nitride film, protects semiconductor devices,especially by absorbing mechanical, electrical and chemical shocksduring a subsequent assembly or packaging process.

Normally, a repair process is performed on semiconductor devices such asmemory devices when their circuits do not properly operate due todefects that occur during manufacturing. The defective circuits may bereplaced with redundant circuits, or a trimming process may be performedin which the characteristics of some circuits are modified for a givenapplication. The repair or trimming process is performed by methods suchas cutting (severing) certain wirings using irradiation of a laser beam.The wirings, portions of which are to be severed by the irradiation of alaser beam, are referred to as fuse lines, and an area including thesevered portions (wiring) and a region surrounding the severed portionsis referred to as a fuse area.

FIG. 1 is a sectional view of a conventional semiconductor device,particularly, a sectional view for showing a portion of a memory celland a fuse area in a dynamic random access memory (DRAM) deviceemploying a multi-level interconnect wiring structure. A cell array areais shown on the left side of FIG. 1. The cell array area includes amemory cell composed of a transistor (14, 16 and 18) and a capacitor(30, 32 and 34), multi-level interconnect wirings 38 and 42, interlayerinsulating films 20, 26, 36 and 40 and a passivation film 44. A fusearea is shown on the right side of FIG. 1. The fuse area includes a fuseline, that is, a bit line 24 connected to the drain region 16 of thetransistor via a bit line contact. The fuse area further includes a fuseopening portion A formed by etching a predetermined depth and width ofthe interlayer insulating films 36 and 40 and the passivation film 44 onthe fuse line 24. The fuse opening portion A is irradiated with a laserbeam, thereby cutting the underlying fuse line 24 (This laser cuttingstep not shown in FIG. 1).

For simplicity, each of the interlayer insulating films 20, 26, 36 and40 is illustrated as a single film but can be formed of a multi-layerfilm. In addition, a lower electrode contact 28 is provided forelectrically connecting the source region 18 of the transistor with thelower electrode 30 of the capacitor. The capacitor is placed on a planedifferent from that of the bit line 24 and thus does not contact the bitline 24. Here, the bit line 24 is described as a fuse line, but the fuseline is not limited to the bit line and may be a word line 14 or anotherwiring. These features are also included in the embodiments of thepresent invention to be described herein.

The fuse area of a conventional semiconductor device having a structureas shown in FIG. 1 has various problems. Particularly, each of theinterlayer insulating films 26, 36 and 40, which are exposed by the fuseopening portion A, is usually formed of an insulating material of thesilicon oxide family. For example, a borophosphosilicate glass (BPSG)film, a phosphorous silicate glass (PSG) film, a spin on glass (SOG)film, a tetra ethyl orthosilicate (TEOS) film and an undoped silicateglass (USG) film which exhibits excellent step coverage are used for theinterlayer insulating films 26, 36 and 40 to alleviate a largestep-difference problem in the cell array area. However, filmscontaining a large amount of impurity, such as the above described BPSGfilm, PSG film, SOG film and TEOS film, in which boron (B) exceeds 5weight percent and phosphorous (P) exceeds 4 weight percent, cannotwithstand much moisture. Moisture may permeate the device through suchfilms. As a result, metal interconnects, for example, the interconnectwirings 38 and 42 formed of aluminum, corrode, thereby degrading thereliability of semiconductor devices.

Referring now to FIG. 2, to solve this problem, Japanese PatentPublication No. Hei 9-69571 suggests forming a guard ring 38′ and 42′ ina quadrilateral shape surrounding a fuse opening portion A as shown inFIG. 2. The guard ring 38′ and 42′ is a two-layer structure, which maybe formed of the same material as multi-level interconnect wirings 38and 42, e.g., aluminum, and may be simultaneously formed with themulti-level interconnect wirings 38 and 42, respectively. In addition,an etch stop layer 34′ having a quadrilateral border shape is formedunder the guard ring 38′ to stop etching of an interlayer insulatingfilm 36 during etching for forming a guard ring opening portion. Theetch stop layer 34′ may be formed of the same material as an upperelectrode 34 of a capacitor, e.g., polysilicon, and may besimultaneously formed with the upper electrode 34.

Accordingly, the guard rings 38′ and 42′ block moisture permeatingthrough the interlayer insulating films 36 and 40, which comprise theside wall of the fuse opening portion A, thereby improving the devicereliability. However, moisture may permeate the device through aninterlayer insulating layer 26 where a guard ring is not formed.Particularly, because the guard rings 38′ and 42′ are formed as amulti-layer structure, moisture may permeate through the interfacesamong the interlayer insulating films 26, 36 and 40 which are vulnerableto moisture coming through the interface between the layers of the guardrings 38′ and 42′. Moreover, a layout area increases due to theadditional formation of guard rings 38′ and 42′, thereby decreasing thehigh integration density of semiconductor devices.

SUMMARY OF THE INVENTION

To solve the above problems, it is a first object of the presentinvention to provide a semiconductor device having a fuse area betterprotected at preventing moisture-permeation and allowing for efficientcutting of fuses.

It is a second object of the present invention to provide a method forforming a fuse area of a semiconductor device, which is better atpreventing moisture-absorption and allows for efficient cutting offuses.

Accordingly, to achieve the first object, the present invention providesa semiconductor device having a multi-level interconnect wiringstructure and a fuse opening portion which allows cutting of a fuseline. The semiconductor device includes a guard ring having aquadrilateral border shape surrounding the fuse opening portion, forblocking permeation of moisture through the fuse opening portion; anetch stop layer formed over the fuse line and at least under the guardring; a multi-layer interlayer insulating layer structure formed on theentire surface of a substrate including the etch stop layer, themulti-layer interlayer insulating layer structure containing the guardring, wherein the fuse opening portion is formed in the multi-layerinterlayer insulating layer structure; and a passivation layer formed onthe entire surface of the substrate including the guard ring and themulti-layer interlayer insulating layer structure and is etched toexpose the fuse opening portion. The guard ring vertically extends fromthe etch stop layer to the uppermost wiring of the multi-layerinterconnect wirings.

The guard ring is formed of a material for forming the uppermost wiringof the multi-level interconnect wirings or the passivation layer.

The semiconductor device also includes a moisture barrier layer over orunder the etch stop layer.

To achieve the second object, the present invention provides a methodfor forming a fuse area of a semiconductor device. Primarily, an etchstop layer is formed over the fuse line and at least in a region inwhich the guard ring is formed. A multi-layer interlayer insulatinglayer structure is formed on a substrate including the etch stop layer.The multi-layer interlayer insulating layer structure is etched untilpart of the etch stop layer is exposed so as to form a guard ringopening portion. The guard ring is formed by filling the guard ringopening portion with a predetermined material. The guard ring openingportion vertically extends from the etch stop layer to the uppermostwiring of the multi-level interconnect wirings.

The guard ring is formed of a material for forming an uppermost wiringor the material of a passivation layer and formed simultaneously withthe uppermost wiring or the passivation layer.

The method also includes the step of forming a moisture barrier layer atleast under the regions in which the guard ring and the fuse openingportion are formed, before or after the step of forming the etch stoplayer.

The etch stop layer may be separately formed in a region in which theguard ring opening portion is formed and in a region in which the fuseopening portion is formed so that the etch stop layer can be used as anetch stop layer when forming the guard ring opening portion and whenforming the fuse opening portion.

According to the present invention, the guard ring is formed at one timeusing the passivation layer or the uppermost wiring, thereby efficientlypreventing permeation of moisture through the interface between theinterlayer insulating films.

In addition, when the guard ring is simultaneously formed with theuppermost interconnect wiring, the passivation layer is etched to exposethe part of the guard ring when forming the fuse opening portion,thereby minimizing an increase in a layout area due to formation of theguard ring.

Moreover, according to an embodiment of the present invention, the etchstop layer is used when an etching process is performed for forming thefuse opening portion so that the thickness of an interlayer insulatingfilm remaining on the fuse line can be accurately controlled as comparedwith a conventional method of forming a fuse opening portion using timedetching, thereby improving the cutting efficiency of a fuse.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objectives and advantages of the present invention will becomemore apparent by describing in detail preferred embodiments thereof withreference to the attached drawings in which:

FIG. 1 is a sectional view of part of a conventional semiconductordevice including a fuse area;

FIG. 2 is a sectional view of part of a conventional semiconductordevice having a guard ring about a fuse area and a plan view of the fusearea;

FIGS. 3 through 7 are sectional views of a semiconductor device forshowing process steps for forming a fuse area according to an embodimentof the present invention;

FIGS. 8A through 10 are sectional views of a semiconductor device forshowing fuse areas formed according to various modifications to thepreferred embodiment of the present invention; and

FIGS. 11 and 12 are sectional views of a semiconductor device forshowing processes for forming a fuse area according to anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A portion of a DRAM device is illustrated in FIGS. 3 through 7. FIG. 3shows a capacitor (130, 132, and 134). A fuse area in this embodiment isconcurrently formed with a cell array area. Using conventionaltechniques, a device isolation film 112 is formed on a substrate 110.Then, a gate electrode 114 and source and drain regions 118 and 116 of atransistor are formed. An interlayer insulating film 120 is deposited onthe entire surface of the substrate 110 including the device isolationfilm 112. Subsequently, the interlayer insulating film 120 is etched toform a contact hole exposing the drain region 116. Next, a conductivematerial, for example, doped polysilicon, metal silicide or a stackedfilm of polysilicon and metal silicide, is processed conventionally toform a contact plug 122 in the contact hole and a bit line 124 extendingacross the region of the device. The bit line 124 on the right of FIG. 3functions as a fuse line. As described above, instead of the bit line124, a word line 114 may be functioning as the fuse line. The height ofthe fuse line in the fuse area may be appropriately adjusted so as toimprove the cutting (severing) efficiency.

An interlayer insulating film 126 is deposited on the entire surface ofthe bit line (the fuse line) 124 and then etched to form a contact holeexposing the source region 118. A conductive material, for example,doped polysilicon, is deposited in the contact hole to form a contactplug 128, and then a lower electrode 130 of a capacitor is formed on thecontact plug 128. In the drawing, the lower electrode 130 is formed insimple stack shape, but may be formed in a different shape such as acylindrical shape or a fin shape. Hemispherical grains may also beformed on the surface of the lower electrode 130. Next, a dielectricfilm 132 is formed on the entire surface of the lower electrode 130, andan upper electrode layer, formed of a conductive material, for example,doped polysilicon, is deposited on the dielectric film 132.

Thereafter, the upper electrode layer is patterned to form an upperelectrode 134 as shown in FIG. 3. The upper electrode layer in the fusearea on the right side of the drawing is patterned in the shape of aquadrilateral border surrounding a region to be irradiated with a laserbeam, that is, a region in which a fuse opening portion is formed. Anupper electrode layer pattern 134′, which is patterned in the shape of aquadrilateral border in the fuse area, functions as an etch stop layerduring etching of interlayer insulating films for forming a guard ringopening portion.

Subsequently, as shown in FIG. 4, a silicon oxide film having excellentstep coverage is deposited on the resultant structure to form aninterlayer insulating film 136, and then a lower interconnect wiring 138is formed.

Next, as shown in FIG. 5, an interlayer insulating film 140 is depositedon the entire surface of the substrate and is then etched to form aguard ring opening portion B in a region where a guard ring is to beformed. In other words, the interlayer insulating films 140 and 136 aresequentially etched to expose the etch stop layer 134′ which is formedin the fuse area in the shape of a quadrilateral border. During theetching process for forming the guard ring opening portion B, a via B′for the connection between interconnect wirings may be simultaneouslyformed. Even though the depths of the guard ring opening portion B andthe via B′ are different in FIG. 5, they can be simultaneously formed byperforming etching until the etch stop layer 134′ and the lowerinterconnect wiring 138 are respectively exposed. The embodiment shownin FIG. 5 is described using a double-level interconnect system.However, if triple-level (or more) interconnect systems are used, theguard ring opening portion B can be formed immediately before the lastwiring is deposited.

Subsequently, as shown in FIG. 6, an uppermost wiring metal is depositedon the entire surface of a resultant structure including the guard ringopening portion B and then patterned to concurrently form an uppermostinterconnect wiring 142 and a guard ring 142′. As seen from FIG. 6, theguard ring 142′ of the present invention is completed at one time, i.e.,using a single deposition and patterning process, so overlay marginsneed to be considered only two times for alignment of upper and lowerlayers. However, when forming the guard ring 38′ and 42′ according tothe conventional method as shown in FIG. 2, overlay margins must beconsidered four times. While the number of overlay margins to beconsidered increases in the conventional method as the number ofinterconnect wiring levels increases, in the present invention, overlaymargins need to considered only two times regardless of the number ofinterconnect wiring levels.

Next, as shown in FIG. 7, a passivation layer 144 comprised of amaterial such as silicon nitride is formed on the entire surface of aresultant structure. The passivation layer 144 and interlayer insulatingfilms 140 and 136 in a region to be irradiated with a laser beam areetched to form a fuse opening portion A. Cutting efficiency of the fuseline 124 is good when the thickness of an insulating film remaining onthe fuse line 124 in the fuse opening portion A is about 3000 Å.

Thus, the fuse opening portion A and the guard ring 142′ are formedhaving a planar layout as shown in plan view in the upper right side ofFIG. 7. A single fuse line 124 passes a single fuse opening portion A inthe fuse area and a single fuse opening portion A is included in asingle guard ring 142′ in FIG. 7. A plurality of fuse opening portionsA, however, may be embraced by a single guard ring 142′. Furthermore, aplurality of fuse lines 124 may pass through a single fuse openingportion A.

The embodiment described above can be modified in various ways asillustrated in FIGS. 8A through 8H. For simplicity, only the region ofthe fuse is shown in FIGS. 8A through 8H.

In forming the fuse area as shown in FIG. 8A, a moisture barrier layer200 is formed on the entire surface of the resultant structure as shownin FIG. 3 to a thickness of more than several tens of angstroms. Themoisture barrier layer 200 is formed of a material that is substantiallyimpervious to moisture, for example, an undoped silicate glass (USG)film, a silicon oxide film containing a low density of impurities, asilicon nitride film or a multi-layer structure comprising a siliconoxide film and a silicon nitride film. In the embodiments describedbelow, a moisture barrier layer is formed of one of the above describedmaterials. Next, the processes described in FIGS. 4 through 7 areperformed over the moisture barrier layer. When the interlayerinsulating films 140 and 136 are etched to form the guard ring openingportion B as shown in FIG. 5, the moisture barrier layer 200 is exposedprior to the etch stop layer 134′. However, the thickness of themoisture barrier layer 200 is thin enough so that it does not functionas an etch stop layer. Accordingly, etching stops at the underlying etchstop layer 134′.

In forming the fuse area shown in FIG. 8B, the moisture barrier layer200 is formed under the etch stop layer 134′. The moisture barrier layer200 under the etch stop layer 134′ is formed before forming thecapacitor 130, 132 and 134 and the lower electrode contact plug 128 ofFIG. 3. In other words, after forming the interlayer insulating film126, the moisture barrier layer 200 is deposited on the interlayerinsulating film 126 to a thickness of more than several tens ofangstroms. Thereafter, the process steps shown in FIGS. 3 through 7 areperformed thereon.

The fuse area shown in FIG. 8C includes a moisture barrier layer 200′ ina similar manner to that of FIG. 8A, but the thickness of the moisturebarrier layer 200′ is greater than 5000 Å, which is much thicker thanthe thickness of the moisture absorption preventing layer 200 of FIG.8A. The moisture barrier layer 200′ is formed thick enough for it tofunction as an etch stop layer during the formation of the guard ringopening portion B shown in FIG. 5. The thick moisture barrier layer 200′can also be used as an etch stop layer when forming the fuse openingportion A. In other words, the passivation layer 144 and the interlayerinsulating films 140 and 136 are sequentially etched until the moisturebarrier layer 200′ is exposed. When the moisture barrier layer 200′ isexposed, the moisture barrier layer 200′ is etched to a predeterminedthickness, (e.g., until the sum of the thicknesses of the interlayerinsulating film 126 and the moisture barrier layer 200′, which remain onthe fuse line 124, is about 3000 Å), thereby forming the fuse openingportion A.

In forming the fuse area of FIG. 8D, the interlayer insulating film 126under the etch stop layer 134′ shown in FIG. 3 is continuously etched toform an interlayer insulating film pattern 126′. The moisture barrierlayer 200 is formed overlying the resulting structure including the etchstop layer 134′ and the fuse line 124. Then the processes of FIGS. 4through 7 are performed thereon.

The fuse area shown in FIG. 8E includes the interlayer insulating film126′ in the same manner as the fuse area shown in FIG. 8D, and includesthe thick moisture barrier layer 200′ in a similar manner to that ofFIG. 8C.

Unlike the above modified examples and embodiment, the fuse area of FIG.8F does not include an etch stop layer 134′. In other words, during theprocess step shown in FIG. 3, the upper electrode layer formed on thefuse area is removed to expose the interlayer insulating film 126. Themoisture barrier layer 200 is formed on the exposed interlayerinsulating film 126 (moisture barrier layer 200 may be formed beforeforming the capacitor 130, 132 and 134 and the lower electrode contactplug 128 of FIG. 3). Then, the process steps shown in FIGS. 4 through 7are performed thereon. In this case, when etching the interlayerinsulating films 140 and 136 to form the guard ring opening portion Bshown in FIG. 5, the interlayer insulating film 126 functions as an etchstop layer. To this end, the interlayer insulating film 126 must beformed of a material having an etching selectivity with respect to theinterlayer insulating films 136 and 140.

The fuse area of FIG. 8G is similar to the fuse area of FIG. 8F, but themoisture barrier layer 200′ is as thick as that shown in FIG. 8C or FIG.8E. The fuse area of FIG. 8H is similar to the fuse area of FIG. 8F, butthe moisture barrier layer 200 is not formed.

Taking into account the modified examples described above, it can beseen that any one of 1) the etch stop layer 134′, 2) the moisturebarrier layer 200′ and 3) the interlayer insulating film 126 mayfunction as an etch stop layer. Accordingly, in this specification, the“etch stop layer” can be any one of the etch stop layer 134′, themoisture barrier layer 200′ and the interlayer insulating film 126, or acombination thereof.

Meanwhile, as described above, best cutting efficiency of a fuse linewas achieved when the thickness of the interlayer insulating filmremaining over the fuse line 124 in the fuse opening portion A was about3000 Å. Other than the embodiments shown in FIGS. 8C, 8E and 8G, thefuse opening portion A is formed, after etching of the passivation layer144 formed of silicon nitride, by timed-etching of the interlayerinsulating films 140 and 136, each of which is formed a material chosefrom a silicon oxide family. However, it is difficult to accuratelycontrol the thickness of the interlayer insulating film remaining on thefuse line 124 using time-etching.

FIG. 9A shows another embodiment of the present invention to alleviatethe above mentioned problem. The upper electrode layer described in FIG.3 is patterned such that the upper electrode 134 is formed in the cellarray area and etch stop layers 134′ and 134″ are also formed in regionswhere the guard ring 142′ and the fuse opening portion A are to beformed, respectively, in the fuse area.

Then, the passivation layer 144 and the interlayer insulating films 140and 136 are etched until the etch stop layer 134″, which is formed inthe lower portion of the fuse opening portion A, is exposed.

Subsequently, as shown in FIG. 9B, the exposed etch stop layer 134″ inthe lower portion of the fuse opening portion A is removed to completethe fuse opening portion A. The thickness of the interlayer insulatingfilm 126 finally remaining on the fuse line 124 is adjusted to about3000 Å. It is preferable that the etch stop layer 134′ under the guardring 142′ is formed to be separated from the etch stop layer 134″ in thelower portion of the fuse opening portion A. If the two etch stop layers134′ and 134″ are connected, a metal from the guard ring 142′ maydiffuse into the etch stop layer 134′, which is formed of, e.g.,polysilicon. If this happens, etching of the etch stop layer 134″ forcompleting the fuse opening portion A may not be performed properly.

Although not shown, it will be appreciated that the etch stop layer 134″may be formed in such a manner as described above and can be used as anetch stop layer during etching for formation of the fuse opening portionA as shown in FIGS. 8A through 8E. Accordingly, the thickness of aninsulating film remaining on a fuse line can be more accuratelycontrolled compared to conventional techniques.

FIG. 10 is a sectional view of a fuse opening portion A′ according toanother embodiment of the present invention. The passivation layer 144is etched to expose a portion of the guard ring 142′. Then, theinterlayer insulating films 140 and 136 are etched self-aligned with theexposed guard ring 142′ as a mask, thereby forming the fuse openingportion A′. Accordingly, an alignment margin increases, and an increasein an overall layout area due to formation of a guard ring can bereduced. In other words, the opening width l of the fuse opening portionA of FIG. 7 is the same as the opening width l of the fuse openingportion A′ of FIG. 10. However, as shown in FIG. 10, an area representedby twice the width l¹ of FIG. 7, (i.e., width 2l₁) can be eliminated,thereby decreasing the overall layout area. In addition, although notshown, it should be appreciated that the modified fuse opening portionA′ as shown in FIG. 10 can be formed as shown in FIGS. 8A through 9B.

FIGS. 11 and 12 are sectional views of a semiconductor device forshowing the processes of forming a fuse area according to anotherembodiment of the present invention. A DRAM device is used herein forillustration. The same processes as those in the embodiment describedabove are performed before a guard ring opening portion is formed. Inother words, as shown in FIGS. 3 and 4, the capacitor is formed in thecell array area, and the etch stop layer 134′ in the fuse area, theinterlayer insulating film 136 and the lower interconnect wiring 138 areformed. Subsequently, as shown in FIG. 11, an uppermost interconnectwiring 142 is formed.

Next, as shown in FIG. 12, the interlayer insulating films 140 and 136are etched to form a guard ring opening portion B. In the embodimentdescribed above by reference to FIG. 5, the guard ring opening portion Bis formed before the uppermost interconnect wiring 142 is formed and theguard ring opening portion B is filled with uppermost wiring metal. Inthe present embodiment, the guard ring opening portion B is formed afterthe uppermost interconnect wiring 142 is formed. Next, a material layersuch as a silicon nitride film is deposited on the entire surface of thesubstrate including the uppermost interconnect wiring 142 and the guardring opening portion B to form a guard ring and a passivation layer 144simultaneously. Thereafter, a fuse opening portion A is formed in thesame manner as those in the previous embodiment. Thus, the fuse openingportion A and the guard ring formed of the same material as thepassivation layer 144 are formed to have a planar layout as shown on theupper right side of FIG. 7.

Further, as in the previous embodiment, a plurality of fuse openingportions A may be included in a single guard ring and a plurality offuse lines 124 may pass through a single fuse opening portion A in thepresent embodiment. Moreover, it will be appreciated that the presentembodiment can be modified as shown in FIGS. 8A through 9B. Methods offorming a fuse area through modification of the present embodiment aresimilar to those of the previous embodiment, and thus detaileddescription of them is omitted.

In the above description, there have been disclosed typical preferredembodiments of the invention. However, this invention should not beconstrued as being limited to these embodiments. For example, a DRAMdevice is used as an example in the above embodiments, but the structureof a fuse area and a manufacturing method thereof can be applied tostatic random access memory (SRAM) devices or other semiconductordevices with a fuse area.

As described above, according to the present invention, a guard ring isformed of the same material as that of the uppermost wiring metal ofmulti-level interconnect wirings or that of a passivation layer, therebyefficiently preventing moisture from permeating through the interfacebetween interlayer insulating films. In addition, permeation of moisturethrough an interlayer insulating film under the guard ring can beprevented by a moisture barrier layer formed of a material havingexcellent resistance to moisture permeation, thereby obtaining reliablesemiconductor devices.

According to one embodiment of the present invention, because the etchstop layer is used during formation of the fuse opening portion A, thethickness of an insulating film remaining on a fuse line can be moreaccurately controlled compared to conventional techniques. Thus, thecutting efficiency of a fuse can be improved.

Also, because a fuse opening portion can be formed by etching interlayerinsulating films in self-alignment with the exposed guard ring as a mask(after a passivation layer is etched to expose a portion of a guardring), an alignment margin and proportionally decreasing a layout areacan be improved.

1. A method for forming a fuse area of a semiconductor memory devicehaving a fuse opening portion for cutting a fuse line, a capacitorincluding an upper electrode, and a guard ring surrounding the fuseopening portion, the method comprising: forming an etch stop layer overthe fuse line and in a region, in which the guard ring is to be formed,concurrently with the upper electrode of the capacitor, the etch stoplayer being formed of the same material as that of the upper electrode;forming a moisture barrier layer over the etch stop layer; forming atleast two levels of interlayer insulating films and at least two levelsof interconnect wirings on the substrate including the etch stop layer,to form a multi-layer interlayer insulating layer structure in a fusearea and to form multi-level interconnect wirings, one of which is anuppermost interconnect wiring being formed in an area other than thefuse area, the interlayer insulating films alternating with theinterconnect wirings; forming a guard ring opening portion having a ringshape surrounding the fuse opening portion by etching the multi-layerinsulating layer structure until the etch stop layer is exposed; whereinsaid forming at least two levels of the interconnect wirings comprisesdepositing an uppermost wiring metal layer over the substrate includingthe guard ring opening portion to fill the guard ring opening portionwith the uppermost wiring metal layer; patterning the uppermost wiringmetal layer to complete the multi-level interconnect wirings and to formthe guard ring; forming a passivation layer over the guard ring; andforming the fuse opening portion by etching the passivation layer andthe multi-layer interlayer insulating layer structure.